A widely used medium for storing data is magnetic tape. Tape cartridges are one of the most popular formats for storing data on tape. Two widely used tape cartridges are the dual reel cartridge and the single supply reel cartridge. In a dual reel tape cartridge, both the supply reel and the take-up reel are housed in the cartridge. In a single supply reel tape cartridge, the take-up reel is built into the tape drive along with an automatic tape threading mechanism. When a tape cartridge is not in use in a tape drive or tape player, it is possible for the reel(s) to rotate idly and cause the tape to lose tension and become partially unwound from the reel. To avoid this problem, tape cartridges often include some type of reel lock.
A common type of reel lock used in single supply reel cartridges includes a locking gear that engages teeth or other projections on the back of a reel drive gear that locks the reel when the cartridge is not installed in a tape drive. A spider washer pushes the locking gear out of the way into a disengaged position unlocking the reel when the cartridge is installed in the tape drive. In this disengaged position, the spider washer spins (with the reel) against the stationary locking gear. The spinning washer sometimes makes the locking gear wobble, oscillate up and down or otherwise vibrate within the free play tolerance of the alignment feature that couples the locking gear to the cartridge housing. At the higher tape speeds of some of the newer generation tape drives, the reel lock vibrating against the hard plastic cartridge housing can be noisy. Embodiments of the invention were developed to reduce these noisy vibrations.